An actual hybrid application

I give up Richard. It would appear this fellow is very young, lacks experience and no formal education in the assorted disciplines necessary.

Now, he wants me to do his research. I'll just put this guy on the ignore list so I don't have to bother with this level of ridiculousness any more.

 

Ok, while I side with Richard and Par, of course... I do think it's possible there is one thing everyone is missing in Mr Know It All's idea:

I think he plans to keep the diesel at peak economical RPM/power range while doing things like docking or motoring slowly through a no wake zone. This would allow electrical power generation to take place while you are not normally using the engine at its peak output. (such as docking or no wake zones)

I think then, he's saying you would use the stored energy you have created from before to put out 40kW if you need to in a pinch. In my posts, I was saying that "pinch" may need to be 12 hours of 40kW output.

I'm not saying it will work, but I'm not sure everyone followed his idea. He is saying:

For a given boat that needs a 40kW engine, that engine is not used at peak "power per liter" if you are going through a no wake zone. So... why not run a 30kW engine at peak "power per liter" all the time and store some of that power in a huge battery bank for when you need the 40kW.

This makes some sense for a weekend boater, but no sense for a long passage under power.

I'm sure it can't work because of the losses in conversion to electrical energy and battery storage...
It also can't work because of the amount of AH in battery storage you need, but that's the point of my previous postings.

 

What else?

Mr know it all, yeah,

we are the idiots Paul, when we reply on such nonsense.

here is the next one:

http://www.boatdesign.net/forums/hybrid/hybrid-system-sunreef-82-needed-34142.html

 

Weekend boaters are perhaps even less indicated for that system, since they usually want to arrive at their destination as soon as possible and moore or drop the anchor there. So the low-engine-load phase would be limited to harbour maneuvring only - a time too short to charge the batteries to any useful level, imho.

 

Good point. I guess that leaves no application at all.

 

The problem with this idea is the loss of power in generating electricity, storing it and retrieving it from the batteries and using it to drive the shaft. This could be about 40-50% of the total engine output.

In comparison, modern marine diesels are designed to be used across a range of power outputs. The attachment shows consumption for a Vetus 170 hp engine. Between 1,500 rpm and 4,000 rpm, the engine efficiency varies from 147 g/hp/h to about 170 g/hp/h. So even if you changed from worst consumption to best, you would only save 13% fuel.

I could see the idea being used in a river barge. They tend to either run flat out against the current, or are idling as the move through locks or go down stream. If the electric motor was powerful enough for manoeuvring, the diesel could be left unused part of the time. You could even use shore power to recharge the batteries at night.

CatBuilder's point about having an auxiliary motor is especially valid here - as much to stop the boat and get out of the channel. You could also use the boat generator to drive the motor (inefficient, but useful for emergency propulsion).

 

Mr know Nothing:

You've come on here and insulted engineers,builders,and designers.

Chew on this:

You need 10kw @ 12 volts which is 833 amps an hour.


12 volts=160 pounds:
http://www.lifelinebatteries.com/rvflyer.php?id=7


$600 each
http://www.invertersrus.com/gpl-8dl.html

For # of hours needed,@833 amps@12 volts to 50% of battery capacity:

12 hours=720 min=175 batteries=14 tons=$105,0000

6 hours=360 min=87 batteries=7 tons=$53,000

2 hours=120 min=29 batteries.=4700 lbs.=$17,600



Read those figures a few times and please stop bothering us.

 

The 12 hours part was the only thing I asked for. Thank you!

 

The idea is about engine downsizing. Say your sailboat hull reaches a comfortable cruising speed at 135 hp (big boat, I know). In the Vetus catalog: http://viewer.zmags.com/publication/c95187af#/c95187af/36

the fuel consumption for VF4.140E is about 200 g / kW @ 135 hp. The VF4.170E lies at 250g/kW when it is cranking out 135 hp. The fuel consumption is 25 % better for the VF4.140E.

A 30 hp electric motor would give you the extra power when necessary.

If the user requires 12 hours running time at 170 hp (30 hp electric), the hybrid is totally unfeasible (battery weight, battery volume, battery costs).

 

The attachment shows consumption for a Vetus 170 hp engine. Between 1,500 rpm and 4,000 rpm, the engine efficiency varies from 147 g/hp/h to about 170 g/hp/h. So even if you changed from worst consumption to best, you would only save 13% fuel.

You are being suckered . The graphs posted assume full loading at the Rpm's shown.

When you can only use a tiny amount of rated power (by proping for 100% throttle and operating at 20%) the fuel used at 20% will be 200% to 300% of what the factory graph shows , because your underloaded.


Yes the concept of loading the engine properly is technically appealing , but the reality of HOW is so expensive , and complex its only of interest to Cruise Ships.

Not many cruisers will pay $50,000 up front to "save" 1/2 GPH under power.

FF